Oh god I've got few replies, this is not cool

It wouldn't bode well for Either. Galactus would probably get cheated out of a few meals. Lobo would eventually get his ass kicked. Or Galactus would try and banish him to another world, like he did with Surfer. Lobo would then terrorize everyone one the planet.

Lobo is Too Ruthless, Galactus would eventually get tired of Lobo defying him and they would go at it in a Slugfest... I see Galactus pounding the sh!t out of Lobo... Lobo regenerating and saying "Is That All You Got" and then the process would repeat.